Patterned conductive layers for sensor assembly and method of making the same

ABSTRACT

An ITO sensor design and method for making the same is optimized to minimize noise from an LCD. The design includes a two layer sensor design having a transmitter line (Tx) placed in a first layer and a receiver line (Rx) placed in a second layer in a diamond-shaped pattern. The diamond shape maximizes the sensitivity of the sensor.

RELATED APPLICATION

The present invention claims priority from U.S. Provisional Patent Application Ser. No. 61/427,645 filed Dec. 28, 2010, and is incorporated herein by reference in its entirety for all purposes as if fully set forth herein.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The invention generally relates to an apparatus and method of making a sensor design for a capacitive sensor, and more particularly to an indium tin oxide (ITO) sensor design for a liquid crystal display (LCD).

2. Discussion of the Related Art

Currently touch capacitive sensors are used widely for a number of different touch screens, e.g., continuous capacitive sensors and discontinuous capacitive sensors. FIG. 1A illustrates a top view of a related art sensor assembly. FIG. 1B illustrates a cross-sectional view of the sensor assembly in FIG. 1A.

Referring to FIGS. 1A-1B, the sensor assembly is generally depicted as reference number 100. The sensor assembly 100 includes a receiver line 102, a transmitter line 104 and an insulator 106 arranged between the receiver line 102 and the transmitter line 104. The receiver line 102 and the transmitter line 104 are arranged in a diamond pattern.

FIG. 2 illustrates a cross-sectional view of a related art sensor of FIG. 1 in a LCD display apparatus. Referring to FIG. 2, the LCD display apparatus is generally depicted as reference number 200. The LCD display apparatus includes a LCD 202 and a sensor assembly 100, with LCD 202 being located underneath the sensor assembly 100. An air gap between the LCD 202 and sensor assembly may be about 0.35 mm, thereby creating a capacitance between the receiver line 102 and the transmitter line 104, e.g., about 2 pF or bigger. In operation the voltage of the VCOM plane (not shown) may change in a square wave manner as shown in FIG. 2 and may have a magnitude of about 7Vp-p. FIG. 4 illustrates an electric field simulation of noise generated in operation of related art device of FIG. 2.

Referring to FIGS. 3 and 4, it shown that the electric field from the VCOM plane (not shown) may go directly to the receiver line 102. More specifically, when the VCOM voltage changes it injects a charge into the receiver line 102 (noise), which leads to measurement error. Therefore, the related art design exposes the receiving line to LCD noise.

Accordingly, there is a need to overcome the problems with the related art described above.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are included to provide a further understanding of the invention and are incorporated in and constitute a part of this specification, illustrate embodiments of the invention and together with the description serve to explain the principles of the invention.

In the drawings:

FIG. 1A illustrates a top view of a sensor assembly according to the related art;

FIG. 1B illustrates a cross-sectional view of the sensor assembly of FIG. 1A;

FIG. 2 illustrates a cross-sectional view of a LCD display touch screen apparatus according to the related art;

FIG. 3 illustrates a voltage diagram of a VCOM plane of the apparatus of FIG. 2;

FIG. 4 illustrates a modeling of the electrical field of the apparatus of FIG. 2;

FIG. 5 illustrates a top view of a sensor assembly according to an embodiment of the invention;

FIG. 6 illustrates a modeling of the electrical field of the sensor assembly of FIG. 5A;

FIGS. 7A and 7B illustrate a top view of a sensor assembly according to another embodiment of the invention;

FIG. 7C illustrates a modeling of the electrical field of the sensor assembly of FIG. 7A;

FIGS. 8A and 8B illustrate a top view of a sensor assembly according to another embodiment of the invention;

FIG. 8C illustrates a modeling of the electrical field of the sensor assembly of FIG. 8A;

FIG. 9A illustrates a top view of a sensor assembly according to another embodiment of the invention; and

FIG. 9B illustrates a cross-sectional view of the sensor assembly according to FIG. 9A.

SUMMARY OF THE INVENTION

Accordingly, the invention is directed to sensor assemblies that substantially obviate one or more of the problems due to limitations and disadvantages of the related art.

An advantage of the invention is to provide sensor design that substantially eliminates LCD noise.

Another advantage of the invention is to provide a two layer sensor pattern to provide better performance for use with current or future capacitive sensor technology.

Additional features and advantages of the invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the invention. The objectives and other advantages of the invention will be realized and attained by the structure particularly pointed out in the written description and claims hereof as well as the appended drawings.

To achieve these and other advantages and in accordance with the purpose of the present invention, as embodied and broadly described, a sensor assembly apparatus includes a conductive material arranged into a plurality of rows and a plurality of conductive electrode patterns arranged over the plurality of rows, wherein at least one of the plurality of rows is coupled to an analog ground to shield the plurality of conductive diamond patterns from electrical noise.

Another aspect of the present invention is directed towards a touch panel assembly. The touch panel assembly includes a patterned layer of conductive material that includes a plurality of electrodes, a plurality of conductive patterns arranged over at least a portion of the plurality of electrodes, and a LCD module arranged under the pattern layer and plurality of conductive patterns. The plurality of electrodes is grounded by an analog ground connection to provide shielding to the conductive patterns.

Yet another aspect of the invention is directed towards a method for manufacturing a sensor assembly. The method includes the steps of providing a substrate, e.g., glass, plastic, and the like. A layer of conductive material is formed over the substrate and forms a patterned conductive material over the layer, wherein the layer of transparent conductive material is grounded. It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are intended to provide further explanation of the invention as claimed.

DETAILED DESCRIPTION OF THE ILLUSTRATED EMBODIMENTS

Reference will now be made in detail to an embodiment of the present invention, an example of which is illustrated in the accompanying drawings.

FIG. 5 illustrates a top view of a sensor assembly according to an embodiment of the invention.

Referring to FIG. 5, the sensor assembly is generally depicted as reference number 500. The sensor assembly 500 includes a receiver line 504 and a transmitter line 502 formed from conductive material, e.g., ITO. The receiver line 504 is formed in a pattern having a diamond shape to increase sensitivity of the senor.

FIG. 6 illustrates a modeling of the electrical field of the sensor assembly of FIG. 5. Referring to FIG. 6, it is shown that noise is reduced or eliminated, that is, the electric field lines from the LCD (not shown) are blocked by transmitter lines 502 and the receiver line 504 can acquire a signal from the transmitter lines 502 and not from other sources. It is noted that other shapes for the receiver line may also be used; however, a larger diamond shaped receiver line has increased parasitic mutual capacitance values between the transceiver lines and receiver lines, which may be out of the dynamic range of a sensor controller (not shown).

FIGS. 7A and 7B illustrates a top view of a sensor assembly according to another embodiment of the invention.

Referring to FIGS. 7A-7B, the sensor assembly 700 includes a receiver line 704 and transmitter line 702, both formed from conductive material, e.g., ITO. The receiver line 704 is formed in a diamond shape to increase sensitivity of the sensor. In addition, the transmitter line 702 also has diamond shaped holes 706. In this embodiment, the parasitic mutual capacitance between transmitter line 702 and receiver lines 704 is reduced by reducing the area in the transmitter line 702, i.e., by creating holes. Moreover, the receiver lines 704 in this configuration have a reduced resistance, but may have some noise as the receiver line could be exposed to LCD noise from the hole as shown in FIG. 7C.

FIGS. 8A and 8B illustrates a top view of a sensor assembly according to another embodiment of the invention.

Referring to FIGS. 8A-8B, the sensor assembly 800 includes a transmitter line 802 and receiver line 804 both formed from conductive material, e.g., ITO. The receiver line 804 is formed in a diamond shape to increase sensitivity of the sensor. In this embodiment, the receiver line 804 includes diamond shaped holes 806. In this embodiment, there is no LCD noise to either the receiver line 802 or the transmitter line 804 as the noise is shielded by the transmitter line 804 as shown in FIG. 8C. The diamond shaped receiver line 802 and diamond shaped holes 806 can cause a higher resistance of the receiver line 802 and thereby can cause the system to slow.

FIGS. 9A and 9B illustrates a top view of a sensor assembly according to another embodiment of the invention.

Referring to FIGS. 9A-9B, a sensor assembly 900 includes a transmitter line 902 and a receiver line 904, both formed from a conductive material, e.g., ITO. The receiver line 902 is formed in a diamond shape to increase sensitivity of the senor. In this embodiment, the receiver line 904 includes diamond shaped holes 906. A diamond shaped floating conductive layer 908, e.g., ITO, is also formed over the transmitter line 902. This floating conductive layer 908 is configured to ensure LCD light travels through both the receiver layer line 904 and the floating layer 908 and thereby provides a consistent LCD brightness. The consisted brightness is thus provided by a first ITO layer (transmit layer 902) and a second layer (receiver layer 904, including floating portion 908).

It will be apparent to those skilled in the art that various modifications and variations can be made in the present invention without departing from the spirit or scope of the invention. Thus, it is intended that the present invention cover the modifications and variations of this invention provided they come within the scope of the appended claims and their equivalents. 

1. A sensor assembly apparatus, comprising: a transmit portion, including a conductive material arranged into a plurality of rows; and a receive portion, including a conductive electrode pattern arranged over the plurality of rows in the transmit portion, wherein at least one of the plurality of rows in the transmit portion is coupled to an analog ground in order to shield the conductive electrode pattern in the receive portion from electrical noise.
 2. The apparatus of claim 1, wherein the conductive material in the transmit portion comprises indium tin oxide (ITO).
 3. The apparatus of claim 1, wherein the conductive electrode pattern comprises a substantially diamond-shaped electrode pattern.
 4. The apparatus of claim 1, further comprising a liquid crystal display (LCD) arranged under the sensor assembly separated by an air gap.
 5. The apparatus of claim 1, wherein the conductive material arranged into a plurality of rows in the transmit portion further comprises a plurality of patterned holes therein.
 6. The apparatus of claim 5, wherein the conductive electrode pattern is arranged over at least a portion of the plurality of patterned holes.
 7. The apparatus of claim 3, wherein the diamond-shaped electrode pattern further comprises a diamond-shaped hole pattern therein.
 8. A touch panel assembly comprising: a transmit portion, including a patterned layer of conductive material that includes a plurality of electrodes; a receive portion, including a conductive pattern arranged over at least a portion of the plurality of electrodes, wherein the plurality of electrodes in the transmit portion is grounded to provide shielding to the conductive pattern in the receive portion; and a liquid crystal display (LCD) module arranged under the receive portion.
 9. The touch panel of claim 8, wherein the conductive pattern comprises an indium tin oxide (ITO) material formed into a diamond-shaped pattern.
 10. The touch panel of claim 8, wherein the conductive material arranged into a plurality of rows in the transmit portion comprises a plurality of patterned holes therein.
 11. The touch panel of claim 10, wherein the conductive pattern is arranged over at least a portion of the plurality of patterned holes.
 12. The apparatus of claim 8, wherein the conductive pattern in the receive portion further comprises a diamond-shaped hole pattern therein.
 13. The apparatus of claim 8, wherein the conductive pattern further comprises a floating indium tin oxide (ITO) pattern.
 14. A method for manufacturing a sensor assembly, the method comprising: providing a substrate; forming a transmit portion over the substrate, including a layer of conductive material; and forming a receive portion over the transmit portion, including a patterned conductive material, wherein the layer of conductive material in the transmit portion is grounded.
 15. The method of claim 14, wherein the conductive material in the transmit portion comprises indium tin oxide (ITO).
 16. The method of claim 14, wherein the patterned conductive material in the receive portion comprises a substantially diamond-shaped pattern.
 17. The method of claim 14, wherein the sensor assembly is used in a liquid crystal display (LCD) apparatus.
 18. The method of claim 14, further comprising forming a floating pattern in at least a portion of the patterned conductive material.
 19. The method of claim 18, wherein the floating pattern comprises a floating indium tin oxide (ITO) pattern.
 20. The method of claim 14, further comprising a diamond-shaped hole pattern in the patterned conductive material of the receive portion. 